Trailers and methods for regulating the distance between a trailer and a connecting rod

Abstract

Trailer with at least one driven wheel, comprising an energy source configured to supply energy to a wheel drive, a braking device for decelerating the at least one wheel, a connecting rod configured to be connected to a towing device and movably mounted on the trailer, a displacement sensor configured to measure the position of the connecting rod relative to the trailer, a speed measuring device configured to determine the driving speed based on a measurement of the speed of the trailer and / or the connecting rod, and an electronic controller, wherein the controller is configured to shift the position of a neutral point relative to the trailer from a zero point depending on the determined driving speed.to calculate a control deviation using the distance between the position of the neutral point and the measured position of the connecting rod, and to use this control deviation to control the wheel drive and / or the braking device.

Description

[0001] The present invention relates to a trailer with a wheel drive and a method for controlling such a trailer.

[0002] State-of-the-art powered trailers use force sensors, particularly strain gauges, to control the trailer drive. These sensors measure the forces occurring between the trailer and the towing vehicle. These force sensors are known to be susceptible to external influences, especially environmental factors such as temperature and humidity fluctuations. Furthermore, the connection between the trailer and towing vehicle in state-of-the-art designs is always rigid and therefore susceptible to axial and lateral forces between the two. In particular, strong vibrations, even resonant oscillations, can occur in the trailer-towing vehicle system. This results in the force sensor generating a large amount of measurement data, which in turn leads to a high processing load for the control unit.It is also difficult to distinguish the measurement data essential for controlling the trailer from the background noise generated by vibrations and other disturbances. This impairs driving comfort and increases energy consumption, among other things.

[0003] A motorized trailer for a bicycle is known from US 2012 / 0037435 A1. The trailer described therein is connected to the bicycle via a tow bar, the tow bar being equipped with a force sensor, and the trailer being equipped with a motor. Depending on the speed difference between the bicycle and the trailer, the force sensor measures a compressive force when the trailer is faster than the bicycle, or a pulling force when the trailer is trailing the bicycle. The motor accelerates the trailer according to the forces measured by the force sensor.

[0004] US 8,365,849 B2 describes a system for towing a trailer. The trailer includes an electric motor, brakes, a drawbar, and a force sensor mounted on the drawbar. Depending on the mechanical forces measured by the force sensor, the trailer is accelerated by the motor or decelerated by the brakes.

[0005] DE 10 2010 051 838 A1 describes a trailer for a bicycle, wherein the trailer includes an electric machine that can function as both a brake and a motor to prevent the trailer from causing a noticeable feedback effect on the bicycle when pushing or braking. To achieve this, various sensors are described. These include a pedal pressure sensor, a brake force sensor integrated into the brake lever, and a force sensor located in the connection between the bicycle and the trailer. The signals from these sensors are transmitted to an electronic logic circuit, which in turn controls the electric machine and / or the brakes. The force sensor determines whether the bicycle is exerting a pulling or pushing force on the trailer, and depending on the measured signals, the motor or brakes are activated to keep the trailer following the bicycle.As an alternative to force measurement, pre-tensioned measuring systems are proposed, in which either a pressure sensor detects pressure changes in a cylinder or a position sensor measures the position of a spring-mounted disc. While such pre-tensioned measuring systems offer a less rigid coupling between the trailer and the bicycle, disruptive, particularly pulsating, feedback effects still remain.

[0006] DE 10 2006 009 862 A1 describes a bicycle push trailer for propelling and braking a bicycle, wherein a battery is mounted as an inertial mass in a frame of the trailer, so that during braking the battery swings forward and during acceleration the battery swings backward. The battery is articulated via a control lever to a position sensor and a Bowden cable. During braking, an electric motor is operated recuperatively via the position sensor, while simultaneously a mechanical brake is activated via the Bowden cable.

[0007] US 2013 / 0311058 A1 discloses a method for controlling a trailer powered by an electric motor.

[0008] EP 3 416 860 A1 relates to a method for controlling a powered trailer and a motor-driven trailer. The method includes, among other things, a step in which a distance between the trailer and the towing vehicle is defined as the neutral position. The deviation of the distance between the trailer and the towing vehicle from the neutral position is measured and output as a distance value. If the distance between the trailer and the towing vehicle is reduced from the neutral position by at least one first distance value, the trailer is electrically braked. If the distance between the trailer and the towing vehicle is reduced from the neutral position by at least one second distance value, where the second distance value is greater than the first distance value, the trailer is mechanically braked, independent of the electrically actuated braking.If the distance between the trailer and the towing vehicle is increased by a third distance value compared to the neutral position, the trailer is accelerated by an electric motor.

[0009] Based on this, the invention aims to enable the most sensitive possible control of a driven trailer.

[0010] The problem is solved by a trailer according to claim 1 and by a method for controlling the distance according to claim 10. Advantageous embodiments are the subject of the dependent claims and the description.

[0011] The trailer according to the invention with at least one driven wheel comprises • an energy source designed to supply energy to a wheel drive, • a braking device for slowing down at least one wheel, • a connecting rod designed to be connected to a towing device and movably mounted on the trailer, • a displacement sensor designed to measure the position of the connecting rod relative to the trailer, • a speed measuring device designed to determine the vehicle speed based on a measurement of the speed of the trailer and / or the connecting rod, and • an electronic controller, and is characterized by the fact that • the controller is designed to ◯ to shift the position of a neutral point relative to the trailer, starting from a zero point, depending on the specific driving speed, ◯ to calculate a rule deviation using the distance between the position of the neutral point and the measured position of the connecting rod and ◯ to control the wheel drive and / or the braking system with the control deviation.

[0012] The trailer has one or more wheels. It can therefore stand upright on its own, only when towed by a vehicle, or be held upright by an operator. At least one of the wheels is driven by a motor. This motor is preferably an electric motor. The electric motor can be a wheel hub motor or mounted on the trailer and drive the wheel via a drive shaft. Furthermore, the trailer has a power source to supply energy to the drive system. For an electric motor, this could be a battery. However, a fuel cell or photovoltaic system can also be used. If an internal combustion engine is used, a corresponding fuel tank and fuel supply are required.In addition to the drive system, the trailer also has a braking system that acts on at least one wheel to decelerate it and thus the trailer. If the trailer has multiple wheels, the drive system and the braking system can be designed to act on different wheels independently. The braking system can be a mechanical brake, such as a disc brake or a drum brake, which brakes the at least one wheel or a shaft attached to that wheel. Alternatively, the braking system can include a device designed to control the drive system so that it generates a braking effect. In the case of an electric motor, this can be regenerative operation of the motor, resulting in electric braking.In the case of an internal combustion engine, this can be a cessation of the fuel supply, so that it does not deliver any drive power in order to use the internal friction of the internal combustion engine as an engine brake, which leads to braking.

[0013] The trailer has a connecting bar designed to be attached to a towing device. A drawbar is used to connect it to a towing vehicle, which is attached to the vehicle using the towing device. A towing vehicle can be, in particular, a bicycle. The trailer can also be pulled by a person or an animal using the towing device.

[0014] The connecting rod is attached to the trailer with a bearing, allowing it to move relative to the rest of the trailer. Suitable bearings, such as linear guides or ball bearings, can be used for this purpose. Depending on the bearing design, the connecting rod can have a varying number of degrees of freedom. The bearing only absorbs forces in directions where it does not provide any degrees of freedom for the connecting rod.

[0015] The trailer is equipped with a displacement sensor. This sensor is designed to measure the position of the connecting rod relative to the trailer. To do this, the sensor determines a point fixed to the connecting rod within a coordinate system that is fixed to the sensor's position. The orientation of the sensor's coordinate system relative to the bearing that supports the connecting rod is fixed. For example, if the bearing is rotatable around a vertical axis of the trailer, the position of the connecting rod relative to the trailer is defined as the position of the connecting rod relative to the part of the trailer that rotates with the bearing. Therefore, a corresponding rotation of the bearing does not change the measured position of the connecting rod relative to the corresponding part of the trailer.Provided the connecting rod is firmly attached to the towing vehicle or towing device, the position of the towing vehicle or towing device relative to the trailer can be calculated by adding a corresponding distance vector.

[0016] The trailer is equipped with a speed measuring device. This device is designed to determine the vehicle's speed. It does this by measuring the speed of the trailer and / or the connecting rod relative to a world coordinate system. The measurement of the trailer's and / or the connecting rod's speed is therefore absolute, relative to the stationary world, and not relative to a moving coordinate system, such as the aforementioned coordinate system of the displacement sensor. The speed measuring device can be configured, according to one embodiment, to perform these measurements.

[0017] The trailer has an electronic controller designed to control the drive and braking systems. The drive and / or braking systems then adjust the applied drive and / or braking force, thus accelerating or decelerating the trailer. The controller can define the control behavior using a control formula. This formula can be, for example, an electronic circuit integrated into the controller or a computer program stored on the controller. The controller itself can be a microcontroller. The controller takes the control deviation as an input signal. The control formula can include components that calculate the control signal proportionally to the control deviation, proportionally to the change in the control deviation, and proportionally to the integral of the control deviation.By designing the control parameters to match the characteristics of the trailer, its drive system, and its braking system, optimal control of the drive and braking system can be achieved. Optimal control can mean achieving one or more control objectives. It is preferable for the control deviation to be as constant and small as possible. Furthermore, it is preferable for any control deviation to be quickly reduced after it occurs. A challenge arises from the fact that disturbances can affect the system. These include, in particular, changes in the speed of the towing vehicle or the towing device. Uneven road surfaces or other environmental conditions, such as varying wind speeds, also constitute disturbances. As soon as such a disturbance affects the control deviation, the controller attempts to minimize it quickly by appropriately controlling the wheel drive and the braking system.Collisions between the connecting rod and other components of the trailer must be strictly avoided.

[0018] The controller calculates the control deviation by determining the difference between a neutral point and the position of the connecting rod. Like the position of the connecting rod, the neutral point is defined relative to the trailer, specifically within the coordinate system of the position sensor. If there is no control deviation, the trailer neither accelerates nor decelerates. The controller uses the vehicle speed to determine the neutral point. The relationship between the neutral point and these measured values ​​can be stored on the controller, for example, in the form of a saved computer program, an algorithm, or a lookup table. The controller is designed such that the neutral point is set relative to the trailer, i.e., within the coordinate system of the position sensor, depending on the vehicle speed. To do this, the controller shifts the neutral point relative to the trailer, i.e., within the coordinate system of the position sensor.zero point fixed to the path sensor coordinate system.

[0019] An advantage of shifting the neutral point depending on a measured speed is that a sensitive control, in which the operator or the towing vehicle is not influenced by the trailer, can be achieved more easily.

[0020] As described above, the control of the wheel drive and the braking system, which causes the trailer to accelerate or decelerate, depends on the controller and the control deviation. It is usually advantageous for the controller not to generate a control signal that leads to strong acceleration or deceleration even with very small control deviations. Measurement uncertainties and inaccuracies in the mechanics or electrical components prevent optimal control from being achieved. Therefore, the controller is typically designed so that a sufficiently large control deviation is required to generate a correspondingly strong control signal that leads to strong acceleration or deceleration. The control strategy should therefore not be too sensitive to the control deviation.A disadvantage of this control strategy is that even under normal operating conditions, large distances must exist between the connecting rod and the trailer to produce a sufficiently large control deviation. If an additional disturbance occurs unexpectedly, this leads to a further displacement between the connecting rod and the trailer. This displacement can be so large that the connecting rod collides with other components of the trailer.

[0021] One solution to this problem would be to increase the range of motion of the connecting rod between its respective end stops. However, the space required for this is detrimental to the trailer's design. The invention solves this dilemma. According to the invention, the controller is designed to change the neutral point used to calculate the control deviation depending on the vehicle speed. At higher speeds, the neutral point can be moved closer to or further away from the trailer's center of gravity, depending on the controller's configuration. This change in the neutral point effectively extends the range of motion available to the connecting rod. In this way, a larger control deviation, enabling more precise control, can be tolerated without risking the connecting rod colliding with the rest of the trailer.This also avoids the need to allocate more building space.

[0022] According to one embodiment of the invention, the trailer is characterized in that the displacement sensor is designed as an inductive displacement sensor, a capacitive displacement sensor or a resistance change displacement sensor.

[0023] The sensors mentioned typically consist of a stationary component and a moving component. A change in their relative position causes a change in an electromagnetic property of the stationary component, which is measured and, after processing with a proportionality factor or a corresponding function, output as a distance measurement signal. Preferably, a sensor target is mounted on the connecting rod, and a signal transducer is mounted on the trailer. This transducer measures a change in the distance between the sensor target and the transducer by detecting a change in inductance.

[0024] The sensors mentioned are characterized by their affordability, robustness, and accuracy. Furthermore, they are electronic components that are particularly easy to integrate with the rest of the electronics system.

[0025] In another version, optical sensors or radar-based sensors are used.

[0026] According to one embodiment, the trailer is characterized in that the connecting rod is slidably mounted on the trailer along its longitudinal axis in the direction of a side facing the trailer and a side facing away from the trailer.

[0027] The bearing arrangement of this design grants the connecting rod only one degree of freedom for relative movement to the trailer. This ensures that the connecting rod can only move along its longitudinal axis in the direction of a side facing the trailer and a side facing away from the trailer. The side facing away from the trailer is closer to the trailer's center of gravity than the side facing away from the trailer. Due to the degree of freedom defined by the bearing, the position of the connecting rod relative to the trailer can be expressed as a scalar distance of the connecting rod to a fixed point on the trailer or in the position sensor coordinate system. The bearing can, in particular, be a linear guide.

[0028] The advantage of using a bearing that allows the connecting rod only one degree of freedom along its longitudinal axis is that improved control can be achieved. Such a bearing restricts the degrees of freedom, making it easier to model the physical processes involved in a change in distance and to account for them with the controller.

[0029] According to one embodiment, the trailer has an additional mounting that allows the displacement sensor and components of the trailer rigidly connected to it to rotate relative to the rest of the trailer. This additional mounting can, in particular, be a mounting that allows rotation about the vertical axis. In such a case, all relative specifications relating to the trailer refer to those components of the trailer that are rigidly connected to the displacement sensor and its coordinate system.

[0030] According to one embodiment, the trailer is characterized in that the calculation rule is designed to shift the neutral point, starting from the zero point located on the longitudinal axis, along the longitudinal axis in the direction of the side facing away from the trailer, by a correction distance that is positively proportional to the determined driving speed minus a zero speed.

[0031] In this implementation, the controller uses a linear relationship to calculate the position of the neutral point. According to this relationship, the neutral point is defined by the correction distance and the zero point located on the longitudinal axis. The neutral point corresponds to the zero point after it has been virtually shifted by the controller along the longitudinal axis away from the trailer's center of gravity by the correction distance, i.e., towards the side furthest from the trailer. The correction distance is calculated using the vehicle speed. This is done by subtracting the zero speed from the vehicle speed and multiplying the difference by a proportionality factor.

[0032] The position of the neutral point p is determined using the zero position p0, the correction distance Δp, the proportionality constant c, the driving speed v and the zero speed v0 according to the following relationship, p=Δp+p0=c(v−v0)+p0.

[0033] This relationship means that when the vehicle speed is zero, the neutral point remains at zero; therefore, no shift of the neutral point occurs. Only when the vehicle speed increases beyond zero does the neutral point shift relative to zero towards the side furthest from the trailer. At lower speeds, the neutral point shifts relative to zero towards the side furthest from the trailer. Thus, at higher speeds, the neutral point moves towards the drawbar, and at lower speeds, it moves away from it.

[0034] The advantage of the described controller design is that it facilitates sensitive control. At high speeds, a large distance can exist between the connecting rod and the trailer-side, yet only a small control deviation is calculated. The connecting rod is therefore located relatively far from the trailer-side. In the event of braking by the towing vehicle, the connecting rod can move considerably before reaching the end of its bearing or colliding with other trailer components. Thus, a correspondingly large control deviation can occur without a collision taking place.

[0035] Conversely, at low speeds, a small control deviation is calculated when the distance between the trailer-side and the drawbar is small. However, as soon as the towing vehicle or coupling device accelerates—and acceleration is typically greater at low speeds than at high speeds—a large control deviation can occur before the drawbar collides.

[0036] The variable displacement of the neutral point allows for a virtual extension of the clearance available to the connecting rod without causing a collision. This is achieved by exploiting the fact that, at high speeds, the connecting rod must maintain a large distance from the side facing the trailer, and at low speeds, a large distance from the side facing away from the trailer, in order to avoid collisions. Consequently, this virtual extension allows for greater tolerance of control deviations.

[0037] It is advantageous to design the controller to operate with larger control deviations. Due to the electronic and mechanical components used, the controller exhibits inaccuracies; for example, the position measurement signal may be affected by noise, or a corresponding analog-to-digital converter may introduce a time delay. These inaccuracies mean that, even with small control deviations, a relatively large proportion of the deviation is attributable to these inaccuracies. Using such an erroneous control deviation to control the drive and braking system could lead to excessively strong or weak acceleration or deceleration. If, as provided by the invention, a large control deviation is used, the corresponding inaccuracies are smaller in relation to the remaining control deviations. Therefore, they do not distort the control signal.

[0038] According to one embodiment, the trailer is characterized in that the controller is designed to calculate the correction distance negatively proportional to the specified driving speed minus the zero speed, if the specified speed is less than a starting speed that is less than the zero speed.

[0039] According to this implementation, there is an initial speed that is lower than zero speed. If the driving speed falls below the limit speed, the previously described linear mathematical function with a positive proportionality factor is no longer used to calculate the correction distance. Instead, a continuously decreasing function is used. This function is designed to seamlessly transition from the function used at higher speeds. Therefore, according to this implementation, at speeds below the initial speed, i.e., at very low speeds, correction distances are calculated that are larger than the correction distance calculated at the initial speed.

[0040] This results in the neutral point being shifted slightly further towards the side opposite the trailer. Therefore, under normal conditions, there is a greater distance between the neutral point and the side facing the trailer. Consequently, wobbling or other irregularities during acceleration do not directly lead to a collision between the connecting rod and other trailer components.

[0041] According to one embodiment, the trailer is characterized in that the controller is designed to activate the wheel drive and / or the braking device only when the amount of the control deviation is greater than a tolerance deviation.

[0042] The advantage of a tolerance deviation is that small control deviations do not immediately trigger the activation of the wheel drive and / or braking system. Small control deviations can arise, in particular, from non-uniform tensile load on the connecting rod. A non-uniform tensile load is typical when the towing vehicle is a bicycle propelled by the rider's pedaling. Especially at high speeds, strong accelerations or decelerations would be necessary to prevent even small control deviations at all times. This would put stress on the wheel drive and braking system. Therefore, incorporating a tolerance deviation reduces the stress on the wheel drive, the braking system, and the entire trailer.

[0043] According to one embodiment, the trailer is characterized in that the controller is designed to calculate the tolerance deviation positively proportional to the specified driving speed.

[0044] It is advantageous to choose a larger tolerance deviation at high speeds. Especially at such speeds, continuous control of the wheel drive and braking system would lead to accelerated wear of these components.

[0045] According to one embodiment, the trailer is characterized by the fact that a mechanical brake actuation device is provided which is designed to mechanically actuate the brake device when a limit distance between the trailer and the connecting rod is undershot.

[0046] According to this design, the trailer has a mechanical brake actuation device for the braking system. This mechanical brake actuation device serves as a redundancy to the electrical control of the braking system via the regulator. The brake actuation device is designed to be mechanically triggered as soon as the connecting rod falls below a certain minimum distance to the trailer. This could be, in particular, a very small distance between a part of the connecting rod and, for example, an end stop. However, another device, such as a protruding drive lug on the connecting rod and a corresponding stop on the trailer, could also be provided to act as the brake actuation device.

[0047] A mechanical brake actuation system offers the advantage of effective braking even in the event of a power failure or slow control. This prevents collisions between the trailer and the towing vehicle, thus avoiding potential damage. A mechanical brake actuation system therefore enhances the trailer's operational safety.

[0048] According to one embodiment, the trailer is characterized by the fact that the mechanical brake actuation direction a) includes a lever designed to be flipped by the connecting rod as soon as the limit distance is undershot, and b) comprises a cable connected to the braking device and the lever and designed to be tensioned by moving the lever.

[0049] In this design, the mechanical brake actuation device is a cable pull. The cable is actuated by a lever that is flipped when the limit distance is undershot by the connecting rod. This design utilizes proven components, making it particularly reliable.

[0050] The object is also achieved by a method according to claim 10 for controlling the distance between a trailer with at least one wheel, a wheel drive and a braking device and a connecting rod designed to be connected to a towing device and movably mounted on the trailer, which performs the steps • Measuring the position of the connecting rod relative to the trailer, • Measuring the speed of the trailer and / or the speed of the connecting rod, • Determining a driving speed using the speed of the trailer and / or the speed of the connecting rod, • Control of the wheel drive and / or braking system using a control deviation, includes and is characterized by the fact that • the position of a neutral point relative to the trailer is shifted from a zero point with increasing driving speed, • the rule deviation is calculated using the distance between the position of the neutral point and the position of the connecting rod.

[0051] The method is particularly suitable for use with the trailer according to the invention. The advantages of the trailer according to the invention and its embodiments described above also apply mutatis mutandis to the method and its embodiments.

[0052] According to one embodiment, the method is characterized by the fact that • the connecting rod is moved along its longitudinal axis in the direction of a side facing the trailer or a side facing away from the trailer, • the neutral point is shifted from the zero point, which is located on the longitudinal axis, along the longitudinal axis in the direction of the side away from the trailer by a correction distance that is positively proportional to the driving speed minus a zero speed.

[0053] According to one embodiment, the method is characterized in that the correction distance is calculated in a negatively proportional manner to the driving speed if the determined driving speed is less than an approach speed that is less than the zero speed.

[0054] According to one embodiment, the method is characterized in that the wheel drive and / or the braking device are only activated if the amount of the control deviation is greater than a tolerance deviation.

[0055] According to one embodiment, the method is characterized by the fact that the tolerance deviation is calculated in a positive proportionality to the driving speed.

[0056] According to one embodiment, the trailer is characterized in that the braking device is mechanically actuated when a limit distance between the trailer and the connecting rod is undershot.

[0057] The invention will now be explained in more detail using an exemplary embodiment. The figures in the accompanying drawings show: Fig. 1: a trailer according to the invention and a bicycle; Fig. 2: a functional diagram of the trailer; Fig. 3: a schematic representation of a distance measuring device; Fig. 4: a schematic representation of an oscillating distance between trailer and towing vehicle; Fig. 5: a schematic representation of the correction distance as a function of the driving speed.

[0058] Fig. Figure 1 shows a trailer 1 according to the invention and a bicycle 2. The trailer 1 and the bicycle 2 are connected by a coupling rod 3. The trailer has a wheel drive, which is not shown separately in this view. The wheel drive propels the trailer 1 so that it follows the bicycle 2 without the cyclist having to exert any muscle power.

[0059] Fig. Figure 2 shows a functional diagram of trailer 1. The diagram depicts the acceleration and deceleration system 4, which includes a wheel drive and a braking system. This system is powered by an energy source 5, which provides the energy required for propulsion. The drive and braking system are controlled by the controller 6. The control is designed so that the cyclist, or any other towing vehicle, is not aware that trailer 1 is following behind the bicycle. To ensure proper control, the distance measuring device 7 measures the distance between the bicycle 2 and trailer 1. This distance is then transmitted to the controller 6.

[0060] Fig. Figure 3 shows a schematic representation of the distance measuring device 7. The distance measuring device 7 has a housing 8 that is rigidly connected to the rest of the trailer 1. A connecting rod 9 projects into the housing. The connecting rod 9 is connected to the slide 10, which is movably mounted on the linear guide 11. The linear guide 11 defines the degree of freedom that the connecting rod 9 can travel during a relative movement with respect to the housing 8. The range of motion of the connecting rod 9 is limited by the wall of the housing on the right side, which the connecting rod contacts with the rubber end stop 12 as soon as the connecting rod 9 has moved as far as possible to the right. On the left side, the range of motion is limited by the rubber end stop 13. The right side corresponds to the side facing away from the trailer and towards the bicycle. The left side therefore corresponds to the side facing the trailer.The corresponding stops in the form of the rubber end stops 12, 13 define a trailer-away end of the path and a trailer-toward end of the path that the connecting rod 9 can travel.

[0061] A sensor target 14 is attached to the connecting rod 9. The displacement sensor 15 is capable of determining the position of the sensor target 14 relative to it. The displacement sensor 15 and its coordinate system are rigidly connected to the housing 8 and thus to the trailer 1. Measuring the position of the sensor target 14 relative to the displacement sensor 15 therefore corresponds to measuring the position of the connecting rod 8 relative to the trailer 1. The displacement sensor 15 is an inductive displacement sensor. The sensor target 14 and the displacement sensor 15 form a displacement sensor.

[0062] The controller 6 is designed to subtract the position of a neutral point from the measured position of the connecting rod and thus calculate the control deviation. Based on this control deviation, the controller 6 actuates the wheel drive and the braking system, accelerating or braking the trailer 1. Due to the linear guide 11, the connecting rod 9 can only move along a defined path relative to the housing 8 and the trailer 1, namely along the longitudinal axis of the connecting rod 9. The neutral point is also located on this longitudinal axis. The control deviation can therefore also be expressed as a distance along the longitudinal axis. Depending on whether the connecting rod is closer to the trailer-away side or closer to the trailer-away side relative to the neutral point, the control deviation is positive or negative.

[0063] As soon as the connecting rod 9 touches the trailer-side rubber end stop 13 and continues to move towards the trailer-side wall of the housing 8, the lever 16 is flipped. It rotates about the bearing point 17. Flipping the lever 16 tensions the cable 18. The cable 18 is connected to the braking device of the trailer 1. The lever 16 and the cable 18 together form a mechanical brake actuation device that activates the braking device as soon as a minimum distance between the trailer 1 and the bicycle 2, as well as between the connecting rod 8 connected to the bicycle 2, is breached.

[0064] Fig. Figure 4 shows a schematic representation of an oscillating distance 19 between trailer 1 and towing vehicle 2, which is caused by the cyclist pedaling. Adjusting this distance 19 by correspondingly accelerating and decelerating trailer 1 would place a high load on the drivetrain.

[0065] Fig. Figure 5 shows a schematic representation of the correction distance as a function of the driving speed, where the correction distance is shown on the horizontal axis and labeled "Position", and the driving speed is shown on the vertical axis and labeled "Speed". In this embodiment, the driving speed corresponds to the trailer speed, but it can also correspond to the bicycle speed or a combination of these two speeds.

[0066] The correction distance serves to shift the neutral point along the longitudinal axis. Consequently, at different driving speeds, no control deviation occurs at different positions of the connecting rod 9 relative to the displacement sensor 15, the housing 8, or the trailer 1.

[0067] The diagram shows the positions of the connecting rod 9 corresponding to four different driving speeds, at which no control deviation occurs. Position 21 corresponds to a zero speed 20. Position 22 corresponds to a higher driving speed. Position 24 corresponds to an approach speed 23. Position 25 corresponds to a driving speed below the approach speed.

[0068] The illustrations for positions 21, 22, and 24 show that the connecting rod 9 must move further towards the right side, away from the trailer, as the vehicle speed increases to prevent any deviation from the control system. This is due to the illustrated correction distance, which increases with speed and is added to the zero position to calculate the neutral point. At zero speed 20, there is no correction distance. The zero point corresponds to the neutral point. In the illustrated state, without any deviation from the control system, the connecting rod 9 is located midway between the side facing the trailer and the side facing away from the trailer. Above zero speed 20, the correction distance is positive, so the neutral point is shifted towards the side facing away from the trailer. Below zero speed 20, the neutral point is shifted towards the side facing the trailer.Accordingly, the connecting rod 9 must be shifted towards the side facing the trailer or the side facing away from the trailer to prevent any deviation from the control system. Below the starting speed 23, the correction distance increases again. Therefore, the connecting rod must move slightly further towards the side facing away from the trailer to prevent any deviation from the control system.

[0069] The speed dependency of the correction distance means that at high speeds, the neutral point, and therefore also the connecting rod 9, is closer to the side facing away from the trailer. This can lead to a large control deviation when braking the bicycle 2 before the connecting rod 9 contacts the end facing the trailer, specifically the rubber end stop 13. Conversely, the speed dependency of the correction distance also means that at low speeds, the neutral point, and therefore the connecting rod 9, is closer to the end facing the trailer. This can lead to a large control deviation when accelerating the bicycle 2 before the connecting rod 9 reaches the end facing away from the trailer, specifically the rubber end stop 12.

[0070] Large control deviations are less affected by noise caused by mechanical and electronic inaccuracies in the components used. A large control deviation thus enables more sensitive control. At very low speeds, the correction distance is chosen so that the neutral point is slightly further away from the side facing the trailer in order to compensate for jerking or wobbling during acceleration.

[0071] Furthermore, in Fig.Figure 5 shows that a tolerance deviation 26 exists. The control deviation must be large enough that the position of the connecting rod 9 lies outside the respective tolerance deviation for the controller 6 to actuate the acceleration and deceleration device 4. The tolerance deviation 26 increases with increasing driving speed. The tolerance deviation prevents the acceleration and deceleration device from being actuated at relatively small control deviations. This protects the acceleration and deceleration device and prevents wear. Reference symbol 1 trailer 2 bicycles 3 stabilizer link 4 Acceleration and deceleration device 5 Energy source 6 regulators 7 Distance measuring device 8 housings 9 Connecting rod 10 sleds 11 Linear guide 12 Rubber end stop facing away from trailer 13 Trailer-facing end stop 14 Sensor target 15 displacement sensors 16 levers 17 storage location 18 cable pull 19 Oscillating distance 20 Zero speed 21 Zero speed position 22 Higher speed position 23 Starting speed 24 Starting speed position 25 Below starting speed position 26 Tolerance deviation QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] US 2012 / 0037435 A1

[0003] US 8,365,849 B2

[0004] DE 10 2010 051 838 A1

[0005] DE 10 2006 009 862 A1

[0006] US 2013 / 0311058 A1

[0007] EP 3 416 860 A1

[0008]

Claims

[1] Trailer (1) with at least one driven wheel, comprising ◯ an energy source (5) designed to supply a wheel drive with energy, ◯ a braking device for decelerating at least one wheel, ◯ a connecting rod (9) which is designed to be connected to a towing device and which is movably mounted on the trailer, ◯ a displacement sensor designed to measure the position of the connecting rod (9) relative to the trailer (1), ◯ a speed measuring device configured to determine the driving speed based on a measurement of the speed of the trailer and / or the connecting rod, and ◯ an electronic controller (6), characterized by , that ◯ the controller (6) is designed to ▪ to shift the position of a neutral point relative to the trailer (1) starting from a zero point depending on the determined driving speed, ▪ to calculate a control deviation with the distance between the position of the neutral point and the measured position of the connecting rod (9) and ▪ to control the wheel drive and / or the braking device with the control deviation. [2] Trailer (1) according to the previous claim, characterized by that the displacement sensor is designed as an inductive displacement sensor, a capacitive displacement sensor or a resistance change displacement sensor. [3] Trailer (1) according to one of the preceding claims, characterized by that the connecting rod (9) is mounted on the trailer (1) so as to be displaceable along its longitudinal axis in the direction of a side facing the trailer and a side facing away from the trailer. [4] Trailer (1) according to the previous claim, characterized bythat the controller (6) is designed to shift the neutral point, starting from the zero point located on the longitudinal axis, along the longitudinal axis in the direction of the side facing away from the trailer by a correction distance which is positively proportional to the determined driving speed minus a zero speed. [5] Trailer (1) according to the previous claim, characterized by that the controller (6) is designed to calculate the correction distance negatively proportional to the determined driving speed minus the zero speed if the determined speed is less than a starting speed which is less than the zero speed. [6] Trailer (1) according to one of the preceding claims, characterized by that the controller (6) is designed to control the wheel drive and / or the braking device only when the amount of the control deviation is greater than a tolerance deviation. [7] Trailer (1) according to the previous claim, characterized by that the controller (6) is designed to calculate the tolerance deviation positively proportional to the determined driving speed. [8] Trailer (1) according to one of the preceding claims, characterized by that a mechanical brake actuation device is provided which is designed to actuate the brake device mechanically when a limit distance is undercut between the trailer (1) and the connecting rod (9). [9] Trailer (1) according to the previous claim, characterized by that the mechanical brake actuation device ◯ comprises a lever (16) which is designed to be moved by the connecting rod (9) as soon as the limit distance is exceeded, and ◯ comprises a cable pull (18) which is connected to the braking device and the lever (16) and is designed to be tensioned by turning the lever (16). [10] Method for controlling the distance between a trailer (1) with at least one wheel, a wheel drive and a braking device and a connecting rod (9) which is designed to be connected to a towing device and which is movably mounted on the trailer (1), comprehensively the steps ◯ Measuring a position of the connecting rod (9) relative to the trailer (1), ◯ Measuring a speed of the trailer (1) and / or a speed of the connecting rod (9), ◯ Determining a driving speed by means of the speed of the trailer (1) and / or the speed of the connecting rod (9), ◯ Control of the wheel drive and / or braking system using a control deviation, ◯ characterized by , that ◯ with the driving speed the position of a neutral point relative to the trailer (1) is shifted from a zero point, ◯ the control deviation is calculated using the distance between the position of the neutral point and the position of the connecting rod. [11] Method according to claim 10, characterized by , that ◯ the connecting rod (9) is moved along its longitudinal axis in the direction of a side facing the trailer or a side facing away from the trailer, ◯ the neutral point is shifted from the zero point located on the longitudinal axis along the longitudinal axis in the direction away from the trailer by a correction distance which is positively proportional to the driving speed minus a zero speed. [12] Method according to claim 11, characterized bythat the correction distance is calculated negatively proportional to the driving speed if the determined driving speed is less than a starting speed which is less than the zero speed. [13] Method according to one of claims 10 to 12, characterized by that the wheel drive and / or the braking device are only controlled if the amount of the control deviation is greater than a tolerance deviation. [14] Method according to the preceding claim, characterized by that the tolerance deviation is calculated positively proportional to the driving speed. [15] Method according to one of claims 10 to 14, characterized by that the braking device is mechanically activated when a limit distance between the trailer and the connecting rod is exceeded.

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